Whether intended in humor or not, the former New York mayor's remark feeds into a perception among critics that the Trump administration often rejects objective facts and tries to confuse the public about what is true.

Trump's rejection of facts dates back at least to his refusal to accept that former President Barack Obama was a U.S. citizen despite being presented with conclusive evidence.

The perception that a fast and loose attitude toward reality followed Trump, and his staff, into the White House was sparked just after Trump took office. Press secretary Sean Spicer asserted that Trump's inaugural crowd was "the largest audience to ever witness an inauguration – period," when photos showed the crowd in Washington was much smaller than the one present for Obama's inauguration.

White House adviser Kellyanne Conway famously defended Spicer's assertion by saying he was working with "alternative facts."

Giuliani also repeated his statement that Trump did not speak to former FBI Director James Comey about the investigation into former national security adviser Michael Flynn, contradicting Comey's claims.

Rudy Giuliani: Former New York City Mayor

Former New York City Mayor Rudy Giuliani speaks during the 2016 Republican National Convention at Quicken Loans Arena in Cleveland, Ohio. During the 2016 presidential campaign, Giuliani endorsed and campaigned with then-candidate Donald Trump. In April 2018, Giuliani joined the legal team defending President Trump in the special counsel's Russia investigation.

Then-President-elect Donald Trump, right, and former New York Mayor Rudy Giuliani pose for photographs as Giuliani arrives at the Trump National Golf Club Bedminster clubhouse in Bedminster, N.J. on Nov. 20, 2016.

In this Wednesday, Sept. 12, 2001 file photo, New York City Mayor Rudolph Giuliani, center, leads New York Gov. George Pataki, left, and Sen. Hillary Clinton, D-N.Y., on a tour of the site of the World Trade Center disaster. While stumping for Donald Trump in Ocala, Fla., on Oct. 12, 2016, former New York City Mayor Rudy Giuliani accused Hillary Clinton of falsely claiming to have been in New York on Sept. 11, 2001. It isn't clear what Giuliani was talking about. On many occasions, Clinton has described being in Washington, where Congress was in session, on Sept. 11 when hijacked jets began striking the World Trade Center and the Pentagon. Flights were still grounded on Sept. 12, 2001, but Clinton traveled to New York City the next day aboard a federal plane. There, she circled the smoldering World Trade Center in a helicopter, then toured ground zero with Giuliani and Pataki.

President Bush greets New York City Mayor Rudolph Giuliani, left, and Governor of New York George Pataki, right, at McGuire Air Force Base, N.J.,, Sept. 14, 2001. On Sept. 11, when asked to predict the death toll, Giuliani answered with his heart rather than his head: "The number of casualties will be more than any of us can bear ultimately." Giuliani went to scores of funerals in the awful days that followed.

President Bush, center, New York City Mayor Rudolph Giuliani, left, and New York Governor George Pataki, second from left, Sen. Charles Schumer, D-N.Y., second from right, and New York City Fire Commissioner Thomas Van Essen, right, look toward the fallen buildings during a tour of the World Trade Center, Sept. 14, 2001 in New York.

Department of Homeland Security Secretary Jeh Johnson (L) and Former New York City Mayor Rudy Giuliani visit the South Tower Refecting Pool during memorial observances held at the site of the World Trade Center on September 11, 2014 in New York City to mark the 13th anniversary of the September 11th terrorist attacks that killed nearly 3,000 people at the World Trade Center, Pentagon and on Flight 93.

Former NYC Mayor Rudolph Giuliani looks over the museum exhibits a day prior to the opening of the National September 11 Memorial Museum on May 14, 2014 in New York.

New York City Mayor Rudolph Giuliani was named Time magazine's Person of the Year in this cover picture released on Dec. 23, 2001. The magazine's editors chose Giuliani "for having more faith in us than we had in ourselves, for being brave when required and rude where appropriate and tender without being trite, for not sleeping and not quitting and not shrinking from the pain all around him."

Conservative evangelical leader Pat Robertson (R) announces his endorsement of former New York City Mayor Rudy Giuliani for the Republican presidential nomination at the National Press Club November 7, 2007 in Washington, DC. Robertson said he selected Giuliani partially based on the former mayor's assurance that he will nominate Supreme Court justices who would rule similar to conservative justices Antonin Scalia and Samuel Alito.

Republican presidential hopefuls (L-R) former Massachusetts Gov. Mitt Romney, Sen. John McCain (R-AZ) and former New York City Mayor Rudy Giuliani participate in a televised debate on Jan. 24, 2008 in Boca Raton, Fla. before the Florida primary on Jan. 29.

Republican presidential hopeful, former New York City Mayor Rudy Giuliani, speaks at the Republican Party of Sarasota County Lincoln Day Dinner in Sarasota, Fla. Jan. 25, 2008.

Former New York Mayor Rudy Giuliani lets out a hearty laugh as he signs a copy of his book, "Leadership" at a breakfast reception before he spoke at the 2007 New Hampshire Republican State Committee annual meeting held at the Palace Theatre in Manchester, NH on Jan. 27, 2007. At the time, Giuliani was considering a 2008 presidential run. At right is Giuliani's wife, Judith.

New York City Mayor Rudolph Giuliani smiles as he takes a break during his final live radio show in this Dec. 28, 2001, file photo at his City Hall office in New York. After eight years of taking calls from New Yorkers on his weekly radio show, Giuliani's term as mayor expired less than four months after the 9/11 attacks.

Mayor Rudolph Giuliani, left, gestures as he announces that New York City appears to be leading the nation's fight against crime on Jan. 5, 1997 at a New York City police precinct. Figures for early 1996 showed a 10.5 percent drop compared to the 3 percent nationwide decrease.

New York Mayor-elect Rudolph Giuliani hugs his wife Donna as a supporter holds a newspaper with a headline declaring Giuliani the city's new mayor at his victory celebration in New York on Nov. 3, 1993.

Andrew Giuliani, left, helps pour champagne on his father New York Mayor Rudolph Giuliani in the Yankees clubhouse after Game 6 of the World Series between the New York Yankees and the Atlanta Braves at Yankee Stadium in New York, Oct. 26, 1996. The Yankees won Game 6 3-2 to clinch the World Series.

01/16

Former New York City Mayor Rudy Giuliani speaks during the 2016 Republican National Convention at Quicken Loans Arena in Cleveland, Ohio. During the 2016 presidential campaign, Giuliani endorsed and campaigned with then-candidate Donald Trump. In April 2018, Giuliani joined the legal team defending President Trump in the special counsel's Russia investigation.

02/16

Then-President-elect Donald Trump, right, and former New York Mayor Rudy Giuliani pose for photographs as Giuliani arrives at the Trump National Golf Club Bedminster clubhouse in Bedminster, N.J. on Nov. 20, 2016.

03/16

In this Wednesday, Sept. 12, 2001 file photo, New York City Mayor Rudolph Giuliani, center, leads New York Gov. George Pataki, left, and Sen. Hillary Clinton, D-N.Y., on a tour of the site of the World Trade Center disaster. While stumping for Donald Trump in Ocala, Fla., on Oct. 12, 2016, former New York City Mayor Rudy Giuliani accused Hillary Clinton of falsely claiming to have been in New York on Sept. 11, 2001. It isn't clear what Giuliani was talking about. On many occasions, Clinton has described being in Washington, where Congress was in session, on Sept. 11 when hijacked jets began striking the World Trade Center and the Pentagon. Flights were still grounded on Sept. 12, 2001, but Clinton traveled to New York City the next day aboard a federal plane. There, she circled the smoldering World Trade Center in a helicopter, then toured ground zero with Giuliani and Pataki.

04/16

President Bush greets New York City Mayor Rudolph Giuliani, left, and Governor of New York George Pataki, right, at McGuire Air Force Base, N.J.,, Sept. 14, 2001. On Sept. 11, when asked to predict the death toll, Giuliani answered with his heart rather than his head: "The number of casualties will be more than any of us can bear ultimately." Giuliani went to scores of funerals in the awful days that followed.

05/16

President Bush, center, New York City Mayor Rudolph Giuliani, left, and New York Governor George Pataki, second from left, Sen. Charles Schumer, D-N.Y., second from right, and New York City Fire Commissioner Thomas Van Essen, right, look toward the fallen buildings during a tour of the World Trade Center, Sept. 14, 2001 in New York.

06/16

Department of Homeland Security Secretary Jeh Johnson (L) and Former New York City Mayor Rudy Giuliani visit the South Tower Refecting Pool during memorial observances held at the site of the World Trade Center on September 11, 2014 in New York City to mark the 13th anniversary of the September 11th terrorist attacks that killed nearly 3,000 people at the World Trade Center, Pentagon and on Flight 93.

07/16

Former NYC Mayor Rudolph Giuliani looks over the museum exhibits a day prior to the opening of the National September 11 Memorial Museum on May 14, 2014 in New York.

08/16

New York City Mayor Rudolph Giuliani was named Time magazine's Person of the Year in this cover picture released on Dec. 23, 2001. The magazine's editors chose Giuliani "for having more faith in us than we had in ourselves, for being brave when required and rude where appropriate and tender without being trite, for not sleeping and not quitting and not shrinking from the pain all around him."

09/16

Conservative evangelical leader Pat Robertson (R) announces his endorsement of former New York City Mayor Rudy Giuliani for the Republican presidential nomination at the National Press Club November 7, 2007 in Washington, DC. Robertson said he selected Giuliani partially based on the former mayor's assurance that he will nominate Supreme Court justices who would rule similar to conservative justices Antonin Scalia and Samuel Alito.

10/16

Republican presidential hopefuls (L-R) former Massachusetts Gov. Mitt Romney, Sen. John McCain (R-AZ) and former New York City Mayor Rudy Giuliani participate in a televised debate on Jan. 24, 2008 in Boca Raton, Fla. before the Florida primary on Jan. 29.

11/16

Republican presidential hopeful, former New York City Mayor Rudy Giuliani, speaks at the Republican Party of Sarasota County Lincoln Day Dinner in Sarasota, Fla. Jan. 25, 2008.

12/16

Former New York Mayor Rudy Giuliani lets out a hearty laugh as he signs a copy of his book, "Leadership" at a breakfast reception before he spoke at the 2007 New Hampshire Republican State Committee annual meeting held at the Palace Theatre in Manchester, NH on Jan. 27, 2007. At the time, Giuliani was considering a 2008 presidential run. At right is Giuliani's wife, Judith.

13/16

New York City Mayor Rudolph Giuliani smiles as he takes a break during his final live radio show in this Dec. 28, 2001, file photo at his City Hall office in New York. After eight years of taking calls from New Yorkers on his weekly radio show, Giuliani's term as mayor expired less than four months after the 9/11 attacks.

14/16

Mayor Rudolph Giuliani, left, gestures as he announces that New York City appears to be leading the nation's fight against crime on Jan. 5, 1997 at a New York City police precinct. Figures for early 1996 showed a 10.5 percent drop compared to the 3 percent nationwide decrease.

15/16

New York Mayor-elect Rudolph Giuliani hugs his wife Donna as a supporter holds a newspaper with a headline declaring Giuliani the city's new mayor at his victory celebration in New York on Nov. 3, 1993.

16/16

Andrew Giuliani, left, helps pour champagne on his father New York Mayor Rudolph Giuliani in the Yankees clubhouse after Game 6 of the World Series between the New York Yankees and the Atlanta Braves at Yankee Stadium in New York, Oct. 26, 1996. The Yankees won Game 6 3-2 to clinch the World Series.